In functional magnetic resonance imaging measurements, one is interested in detecting tumor tissue based on a harmonic analysis of the data [3]-[5]

There are two strangenesses here: First of all functional magnetic resonance imaging (fMRI) is not (primarily) interested in detecting tumor tissue. MRI without the ‘f’ might be interested in tumor detection. Second, harmonic analysis is not necessarily (and indeed rarely) used for fMRI analysis, and indeed it will be difficult (impossible?) with event-related fMRI. However, harmonic analysis by Fourier transform for image reconstruction is embedded in the MR-scanner.